On the role of aging in carcinogenesis

We have studied cancer age-incidence patterns for the most common cancers in Connecticut from 1935 to 1994 and in locations throughout the world in the 1975 and 1990 eras. We defined "Age 1/2" as the age at which half the incidence occurs in any given year or era. In every population, we found the cancers could be ranked in the same order according to "Age 1/2", i.e., testis < ovary, corpus uterus, breast < stomach, colon, rectum, prostate. This order of cancers according to "Age 1/2" does not correlate with the order according to age-standardized rates, and "Age 1/2" values exhibit less than 10% the variability of age-standardized rates over time and place. We conclude that the determinant of "Age 1/2" is independent of the determinant of age-standardized rates and suggest that "Age 1/2" is determined by host genes that may vary among tissues of tumor origin but are common to all people.